The present invention relates to a trailer van construction and particularly to the construction of side walls for a trailer van.
The maximum vertical height of a trailer van is limited by governmental standards, e.g., standard bridge clearances. The height of a floor of a trailer van above ground is limited by the size and mounting requirements of the front and rear wheel trucks or carriages. The front wheel carriage for the trailer van is usually incorporated into the cab portion of a truck-trailer and the front end of the trailer van is supported thereon. The rear end of the trailer van is supported on a wheel carriage fixed to and beneath the floor of the trailer van. In the construction of cabs and trailer vans there has developed a difference in the above ground height between the front end of the trailer van and the rear end of the trailer van. As a result, the point of maximum height of the trailer van is at the front end of the trailer van and the floor and roof of the trailer van slope downwardly to the rear end of the trailer van. Typically, the vertical extent or height of the rear end of the trailer van is 7 inches below the top of the front end of the trailer van.
In loading trailer vans, dock workers attempt to fill all available space in the trailer van for maximum efficiency and maximum pay load. Accordingly, if additional space can be formed in the trailer for storing additional goods, a greater efficiency and space utilization can be obtained. For this reason various attempts have been made to utilize the wedge of space at the top of the trailer van defined between a plane parallel to the ground and the plane of the roof, both planes intersecting at the top front edge of the trailer van. Typically, these attempts have involved the building of a trailer van with a roof which is parallel to ground level. The floor is non-parallel with the roof and slopes downwardly from the front end of the trailer van to the rear end of the trailer van. The side walls of the trailer van then must have an irregular shape with a vertical extent at the rear of the trailer van which is greater, typically seven inches greater, than the vertical extent at the front end of the trailer van.
An example of a truck-trailer having a trailer van with a front end which is higher than the rear end of the trailer van and with irregular side walls is disclosed in U.S. Pat. No. 2,872,240 (Class 296-28). In the trailer van disclosed in this patent, each side is formed from a longitudinally extending sheet. This, of course, requires special cutting of each sheet in order to form each side wall with the desired irregular shape.
In many conventional trailer vans, the side walls are formed from a plurality of rectangular sheets which are arranged side by side, like a fence. An example of a trailer construction of this type is disclosed in U.S. Pat. No. 3,393,920 (Class 280-106). In this type of construction the sheets are secured together by posts to form an elongate panel. The bottom edge of the panel is secured to a bottom or floor frame member and the marginal edge portion of the panel is secured to an elongate top rail or frame member. Typically the elongate top frame member includes a depending plate portion to which the panel is secured, laterally extending flanges adjacent the top edge of the frame member for supporting the roof, and a capping flange which extends outwardly from the plate portion for extending over the top edge of the sheets and posts. This latter flange forms a cover for the top edges of the panel formed from the sheets and posts. Additionally, a cable-covering flange extends outwardly over the capping flange and is adapted to receive thereunder a cable for supplying electricity to electric lamps mounted on the top frame member along the length thereof.
To form the side walls of this type of trailer van with an irregular shape, so that the roof is parallel to ground level, each sheet for one side wall panel is cut with a different length and preferably cut at an angle. Then, the sheets must be aligned in proper relationship with the shortest sheet at one end and the longest sheet at the other end of the panel formed from the sheets. Since cutting of the sheets at an angle is awkward and time consuming, it is more likely that the sheets will be cut in different lengths, with the cut being perpendicular to the side edges of each sheet. Then the sheets are assembled to form the elongate panel with a stepped top edge and the posts are secured to overlapping side edges of the sheets. Of course, this means that the capping flange will only engage the extending upper corners of the sheets or the posts. Also, there is still the problem of cutting the sheets in different lengths and then aligning the sheets in proper relationship to each other. This results in a significant increase in the cost of making and assembling a side wall with an irregular shape over the cost of making and assembling a rectangular side wall.
It is, therefore, a primary object of the present invention to provide in a trailer van construction a side wall in which no special cutting or special arrangement of each sheet for one side wall is required to provide each side wall with the desired irregular shape.